This is what happend, the car was running but not great, pulled the plugs and cleaned and regaped them,then car would not start again, no fire to the plugs,opened distibutor, points were pited so put in a new set and condenser,still no fire, checked coil lead and no fire when cranking over,had another used coil put that in,still no fire from the coil lead, ok I figure It's no good ether. Called local volvo dealer,they said $500 for new one or I could put in a regular coil,bought a externaly mounted coil and spliced it into the old switch,got 12volts to the coil but nothing out of the neg side or the coil lead when cranking over. Where do I go from here,any help please.

Start simple.
If you have a test light, clip it to a good ground and turn on the ignition. Verify voltage to the coil by touching it to the "+" side of the coil (light on). Remove the dizzy cap and watch to see that the rotor actually goes round and round while doing the next test. Touch the lead to the "-" side of the coil or to the lead at the dizzy. Have an accomplice crank it over. The light should go on and off. If it doesn't you have a short in the low-tension circuit in the dizzy, check to see that the path from the points to the coil lead ("-") isn't grounded anywhere and that the points actually open. If the rotor didn't go round and round, you need to find out why and fix that. Grab the rotor and try to turn it by hand, it should only go a little way an stop to be returned under spring pressure (I've had a rotor drive tang shear off).

Next test for spark as described below. A screwdriver inserted in the coil high-tension lead and resting near a ground will give a decent gap. You will hear the snap. No snap means bad coil IF the above two tests are successful.

If you are good there, Reattach the dizzy cap, check the firing order (and direction of rotation and correct #1 position). Make certain the leads are in the cap and on the plugs firmly!

If it still won't go, check the wires for continuity as one or more may have been broken in all the labor.

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Mike!

Thanks for your help,found the problem,it was the insolator broken,letting it ground out.

Glad it was "simple," My first car had a similar issue but I didn't discover it for three months (had to abandon it as I was on the way to college). I was pretty embarrassed when I found that a simple points set would have worked fine and I could have avoided about $600 of hassle!

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Mike!

OK, my two cents.
INFREQUENTLY, but it has happened to me and others, the bolt clamping the points, condenser wire and the low tension line from the coil to the distributor body, (through no fault of your own), makes contact with the distributor body, and......no spark, nothing. There is an insulator between insulating washers through all of which the bolt passes. Disassemble carefully, and make certain that the bolt is in fact isolated from touching the distributor body - centered in the larger hole in the dist. body, carefully reinstall points, hook up condenser wire and coil wire, add washer and tighten 7mm nut accordingly. Try it now and I'll betchur good.

three thumbs up. thanks again.

Cleaning the plugs won't make it not start! you must have done something else wrong like put the plug wires on wrong,the firing order is counter clockwise,go back to the original coil,I owned a Foreign Auto part store for more than 20 yrs and its never the coil,now that the plugs are gas foweled they won't fire either,so replace the plugs also. The best way to check a coil is pull the coil wire from the dist. and hold it about 1/4 inch away from the block and snap the points open with you finger,it should fire the coil. Richard

Thanks for your help, It was the Insolator at the condenser grounding.

I am not sure what caused the problem, but like others have said here, it probably is not the coil. Probably best put your original coil back in and find the problem.
A note about Bosch coils. Most of them have built in ballast resistance, if you bought a coil off the shelf, it most likely does not have built in resistance. You must purchase a separate ballast resistor and place it in-line on the ignition wire. I believe the resistor should have 1.2 to 1.9 ohms of resistance.
Tom